Sweet Potato Sheet Cake with Marshmallow Frosting

If fall had a flavor, this Sweet Potato Sheet Cake would be it. Imagine a cake that’s moist, tender, and full of warm spices, topped with a billowy cloud of marshmallow frosting that’s sweet, silky, and just the right amount of indulgent. Add a sprinkle of toasted nuts for crunch, and you’ve got a dessert that feels cozy, celebratory, and downright irresistible.

It’s the kind of cake that makes you want to grab a fork straight from the pan. The sweet potato purée gives it this naturally soft texture and subtle sweetness, while the spices—cardamom and cinnamon—wrap around you like a warm hug. Then comes the frosting: glossy, marshmallowy perfection that feels like the grown-up version of roasted marshmallows at a campfire. Trust me, you’re going to fall hard for this cake.

Why You’ll Love This Recipe

This one’s more than just a cake—it’s a whole experience. Whether you’re serving it at a holiday dinner, bringing it to a potluck, or just baking it because you need a pick-me-up, it’s guaranteed to impress. Here’s why:

Versatile

This sheet cake can easily swing from casual family dessert to show-stopper at Thanksgiving. It’s big enough to feed a crowd, but simple enough for a cozy weekend bake.

Flavorful

Sweet potato adds natural sweetness and depth, while cardamom and cinnamon bring warmth and complexity. It’s like pumpkin spice’s chic cousin.

Gorgeous Texture

Moist, tender cake topped with silky, fluffy marshmallow frosting. Each bite is a balance of soft, airy, and a little toasty.

Playfully Customizable

Add toasted nuts for crunch, swirl in orange zest, or even torch the marshmallow topping for a golden, campfire-style finish.

Crowd-Pleasing

Kids love the marshmallow frosting, adults love the spice-infused cake—it’s a win all around.

Recipe Origin

Sweet potato desserts have long been a Southern tradition, from pies to puddings. This recipe takes inspiration from that rich culinary heritage but gives it a modern twist with sheet cake simplicity and a playful marshmallow crown. It’s comfort food with a touch of whimsy.

Kitchen Tools You’ll Need

• Saucepan (to make sweet potato purée)
• Stand mixer or hand mixer
• Large mixing bowls
• Whisk and spatula
• 9×13-inch sheet pan
• Parchment paper (optional, for easy removal)
• Offset spatula (for spreading frosting)

Ingredients in Sweet Potato Sheet Cake with Marshmallow Frosting

Here’s the beauty of this recipe—it’s indulgent but made with ingredients you probably already have on hand. Let’s break it down:

Sweet Potato Purée

Sweet Potatoes: Naturally sweet and earthy, they’re the star of the show.
Water: Just a splash to help the purée come together smoothly.

Cake

All-Purpose or Gluten-Free Flour: A sturdy base that holds everything together.
Baking Powder & Baking Soda: The dream team for lift and fluff.
Cardamom & Cinnamon: Spices that bring warmth, coziness, and that irresistible aroma.
Salt: Balances sweetness and sharpens flavors.
Butter: Melted for richness and a tender crumb.
Sugar: Sweetens the cake without overpowering the sweet potato.
Sweet Potato Purée: Adds moisture, flavor, and a velvety texture.
Orange Juice: Brightens the flavor and keeps the cake fresh and light.
Egg Yolks & Whites: Yolks add richness while whipped whites create a fluffy, light crumb.
Vanilla Extract: Deepens the cake’s flavor with warm, aromatic notes.
Natural Food Coloring (optional): A fun way to give the cake a golden-orange glow.

Marshmallow Topping

Sugar: Creates that glossy, sweet structure.
Egg Whites: Whipped to peaks for a fluffy, meringue-like consistency.
Vanilla Extract: Adds warmth and balances the sweetness.
Salt: A pinch to highlight all the flavors.
Cream of Tartar or Lemon Juice: Stabilizes the egg whites for a perfect marshmallow fluff.

Nut Topping (Optional)

Pecans or Walnuts: Toasted for crunch, nuttiness, and a rustic finish.

(Note: the full ingredients list, including measurements, is provided in the recipe card directly below.)

Instructions

Let’s walk through the steps to bring this cozy dessert to life:

Make the Sweet Potato Purée

Peel and cube the sweet potatoes. Simmer in a saucepan of water until tender. Drain and blend until smooth with a splash of water. Set aside to cool.

Mix the Dry Ingredients

In a large bowl, whisk together the flour, baking powder, baking soda, cardamom, cinnamon, and salt.

Combine the Wet Ingredients

In another bowl, whisk together melted butter, sugar, sweet potato purée, orange juice, egg yolks, vanilla, and optional food coloring.

Whip the Egg Whites

In a clean bowl, whip the egg whites to stiff peaks. This step adds airiness and keeps the cake soft and light.

Fold It All Together

Gently fold the dry ingredients into the wet, then carefully fold in the whipped egg whites. This creates a luscious, airy batter.

Bake

Pour the batter into a greased 9×13-inch pan. Bake until golden, springy, and a toothpick inserted in the center comes out clean. Let cool completely.

Make the Marshmallow Frosting

In a heatproof bowl set over simmering water, whisk sugar, egg whites, vanilla, salt, and cream of tartar until the sugar dissolves. Then beat with a mixer until glossy peaks form.

Frost the Cake

Spread the marshmallow topping generously over the cooled cake. Use swoops, swirls, or peaks for a playful look. If you’re feeling bold, toast it lightly with a kitchen torch for that campfire vibe.

Add Toppings

Sprinkle with toasted pecans or walnuts if desired.

Slice and Serve

Cut into squares and serve! The fluffy frosting paired with the spiced, moist cake will win everyone over instantly.

Chef’s Pro Tips for Perfect Results

• Cool Before Frosting: If the cake’s warm, the marshmallow topping will slide right off. Patience pays off.
• Torch It: Lightly toasting the marshmallow topping makes it taste like roasted marshmallows by the fire.
• Toast the Nuts: Don’t skip this step—toastiness adds depth and crunch.
• Don’t Overmix: Folding gently keeps the cake fluffy.

Nutrition Facts

Servings: 12–16 squares
Calories per serving: ~340
Prep Time: 25 minutes
Cook Time: 35–40 minutes
Total Time: About 1 hour 10 minutes

How to Serve Sweet Potato Sheet Cake with Marshmallow Frosting

• Holiday Table: A standout dessert for Thanksgiving or Christmas.
• Casual Gatherings: Slice into neat squares and serve straight from the pan.
• With Coffee or Tea: The spiced cake pairs beautifully with warm drinks.
• Make It Extra: Add a drizzle of caramel or chocolate sauce for indulgence.

Make-Ahead and Storage Tips

• Make Ahead: Bake the cake a day early; frost just before serving.
• Storage: Keep frosted cake covered at room temperature for up to 2 days. For longer storage, refrigerate.
• Freezing: Freeze the unfrosted cake for up to 2 months. Thaw, then frost before serving.

Variations to Try

• Pumpkin Swap: Use pumpkin purée instead of sweet potato for a different spin.
• Spiced Up: Add nutmeg, ginger, or cloves for a deeper spice kick.
• Nut-Free: Skip the nuts for a smoother bite.
• Chocolate Lovers: Fold in mini chocolate chips before baking.

Additional Tips

• Room-Temp Eggs: They whip better and blend seamlessly into batter.
• Citrus Boost: Add orange zest along with juice for extra brightness.
• Presentation: Use an offset spatula to swirl the frosting into decorative peaks.

FAQ Section

Q1: Can I use canned sweet potato purée instead of fresh?
A1: Yes! Just make sure it’s pure sweet potato, not a pie filling with added sugar.

Q2: Do I need a kitchen torch for the frosting?
A2: Nope! It’s delicious un-toasted, but a torch adds that roasted marshmallow flavor.

Q3: Can I make this gluten-free?
A3: Yes! Use a measure-for-measure gluten-free flour, and it works beautifully.

Q4: Can I use pumpkin instead of sweet potato?
A4: Absolutely. The flavor will shift slightly but still be wonderful.

Q5: How do I keep the frosting fluffy?
A5: Make sure to whip until stiff peaks form and frost once the cake has cooled.

Q6: Can I make cupcakes instead of a sheet cake?
A6: Definitely! Just adjust the baking time to about 18–22 minutes.

Q7: Can I skip the food coloring?
A7: Yes—it’s optional and doesn’t affect flavor, just appearance.

Q8: How long does the frosting hold up?
A8: Best the day it’s made, but it will stay soft and fluffy for about 2 days.

Q9: Can I use a different frosting?
A9: Cream cheese frosting is another dreamy option with this cake.

Q10: Can I freeze leftovers?
A10: Freeze unfrosted cake only. Marshmallow frosting doesn’t freeze well.

Conclusion

Sweet Potato Sheet Cake with Marshmallow Frosting is the kind of dessert that turns an ordinary day into something special. With its spiced, tender crumb and playful marshmallow topping, it’s a celebration in every slice. Whether you serve it for the holidays, a birthday, or just because, it’s guaranteed to make people smile.

So go ahead—whip up this beauty, grab a fork, and savor the sweet, spiced magic.

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